1. Field of the Invention
This invention relates to an air valve device for an inflatable article, more particularly to an air valve device which ensures air-tightness when in a closed position.
2. Description of the Related Art
A conventional air valve device for an inflatable article, such as that disclosed in U.S. Pat. No. 7,401,619 B2, generally includes a valve seat, a movable member, and a biasing member. The valve seat includes a seat body and a tubular wall extending axially from the seat body. The seat body has a central mounting hole and a plurality of communicating holes arranged around the central mounting hole. The movable member includes a plunger which has a connected end that extends through the mounting hole to engage a valve disc, and a head that is operable to move the valve disc from a closed position, where the valve disc is in air-tight engagement with the seat body to shut off the communicating holes, to an opened position, where the valve disc is disengaged from the seat body to permit air to flow through the communicating holes, and an elastomeric seal ring which is attached to the valve disc to ensure air-tight engagement between the valve disc and the seat body. The biasing member is disposed to surround the plunger so as to bias the movable member to the closed position. However, due to the poor wearability inherent with the elastomeric seal ring, long-term subjection of the elastomeric seal ring to relatively large pressure within the inflatable article might result in undesired deformation of the elastomeric seal ring, which may cause air leakage from the inflatable article.